The goal of this training grant is to prepare Inna Maltseva, O.D. for a career as an independent investigator of basic mechanisms of corneal disease with a focus on cell biology. Developmental Plan. A five-year research career development plan is proposed to supplement her previous clinical training with advanced training in the basic science disciplines of cell biology, molecular biology, and microbiology as they relate to corneal disease. The proposed program integrates didactic coursework, seminars. and laboratory research experience in state-of-the-art methodologies at the University of California, Berkeley (UCB) and University of California, San Francisco (UCSF). Dr. Maltseva activities will be supervised by two mentors: Suzanne M.J. Fleiszig, O.D., Ph.D. (School of Optometry, UCB) and Carol Basbaum, Ph.D. (Department of Anatomy, UCSF). Research Plan. Microbial keratitis remains one of the most destructive diseases of the cornea, leading to blindness. To prevent this, the human eye produces a spectrum of antimicrobial peptides including human beta-defensin-2 (hBD-2). Its expression is dramatically induced by various stimuli including Gram-negative bacteria. Paradoxically, despite multiple anti-bacterial defense systems, extended use of contact lenses predisposes the cornea to serious infection by Pseudomonas aeruginosa. We have reproduced this phenomenon in vitro and observed that it is correlated with a profound defect in the ability of corneal cells to produce hBD-2 in response to P. aeruginosa culture supernatant. To understand this defect we need to understand the mechanisms controlling the production of hBD-2 by corneal cells in response to bacteria in the absence of contact lenses. This will lay the groundwork for comparisons between contact lens-exposed and non-exposed cells. The focus will be on dissecting signal transduction mechanisms leading to new transcription of hBD-2 (Specific Aim 1 ), defining transcription factor (s) (Specific Aim 2) and the effect of contact lens wear on this pathway (Specific Aim 3). The results of the proposed study will provide new insight into bacterial-epithelial interactions in the eye. Furthermore, the knowledge provided by the investigation could suggest pharmacological intervention during corneal bacterial infection.